On Thu, 24 Oct 2024 23:59:17 +0800 Li Huafei <[email protected]> wrote:
> Use guard(mutex)() to acquire and automatically release ftrace_lock, > fixing the issue of not unlocking when calling cpuhp_setup_state() > fails. > > Fixes smatch warning: > > kernel/trace/fgraph.c:1317 register_ftrace_graph() warn: inconsistent returns > '&ftrace_lock'. > Looks good to me. Acked-by: Masami Hiramatsu (Google) <[email protected]> Thank you, > Fixes: 2c02f7375e65 ("fgraph: Use CPU hotplug mechanism to initialize idle > shadow stacks") > Reported-by: kernel test robot <[email protected]> > Reported-by: Dan Carpenter <[email protected]> > Closes: https://lore.kernel.org/r/[email protected]/ > Suggested-by: Steven Rostedt <[email protected]> > Signed-off-by: Li Huafei <[email protected]> > --- > Changes in v2: > - Use guard() to acquire and automatically release ftrace_lock. > --- > kernel/trace/fgraph.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c > index 41e7a15dcb50..cd1c2946018c 100644 > --- a/kernel/trace/fgraph.c > +++ b/kernel/trace/fgraph.c > @@ -1252,7 +1252,7 @@ int register_ftrace_graph(struct fgraph_ops *gops) > int ret = 0; > int i = -1; > > - mutex_lock(&ftrace_lock); > + guard(mutex)(&ftrace_lock); > > if (!fgraph_initialized) { > ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "fgraph_idle_init", > @@ -1273,10 +1273,8 @@ int register_ftrace_graph(struct fgraph_ops *gops) > } > > i = fgraph_lru_alloc_index(); > - if (i < 0 || WARN_ON_ONCE(fgraph_array[i] != &fgraph_stub)) { > - ret = -ENOSPC; > - goto out; > - } > + if (i < 0 || WARN_ON_ONCE(fgraph_array[i] != &fgraph_stub)) > + return -ENOSPC; > gops->idx = i; > > ftrace_graph_active++; > @@ -1313,8 +1311,6 @@ int register_ftrace_graph(struct fgraph_ops *gops) > gops->saved_func = NULL; > fgraph_lru_release_index(i); > } > -out: > - mutex_unlock(&ftrace_lock); > return ret; > } > > -- > 2.25.1 > > -- Masami Hiramatsu (Google) <[email protected]>
